1. Technical Field
The present invention relates to an inertial sensor and a method for measuring acceleration using the same.
2. Description of the Related Art
Recently, an inertial sensor has been used as various applications, for example, military such as an artificial satellite, a missile, an unmanned aircraft, or the like, vehicles such as an air bag, electronic stability control (ESC), a black box for a vehicle, or the like, hand shaking prevention of a camcorder, motion sensing of a mobile phone or a game machine, navigation, or the like.
The inertial sensor generally adopts a configuration in which a mass body is adhered to an elastic substrate such as a membrane, or the like, in order to measure acceleration and angular velocity. Through the configuration, the inertial sensor may calculate the acceleration by measuring inertial force applied to the mass body and may calculate the angular velocity by measuring Coriolis force applied to the mass body.
In detail, a scheme of measuring the acceleration and the angular velocity using the inertial sensor is as follows. First, the acceleration may be calculated by Newton's law of motion “F=ma”, where “F” represents inertial force applied to the mass body, “m” represents a mass of the mass body, and “a” is acceleration to be measured. Among others, the acceleration a may be obtained by sensing the inertial force F applied to the mass body and dividing the sensed inertial force F by the mass m of the mass body that is a predetermined value. Further, the angular velocity may be calculated by Coriolis force “F=2 mΩ×v”, where “F” represents the Coriolis force applied to the mass body, “m” represents the mass of the mass body, “Ω” represents the angular velocity to be measured, and “v” represents the motion velocity of the mass body. Among others, since the motion velocity V of the mass body and the mass m of the mass body are values known in advance, the angular velocity Ω may be calculated by detecting the Coriolis force F applied to the mass body.
Meanwhile, the inertial sensor according to the prior art includes a piezoelectric body that is formed on a membrane so as to drive a mass body or sense a displacement of the mass body, as disclosed in Korean Laid-Open Patent No. 10-2011-0072229. However, when measuring acceleration by sensing the displacement of the mass body using the piezoelectric body as in the prior art, it is difficult to measure static DC acceleration (in particular, gravity acceleration) due to the dissipation of generated charges or characteristics of the piezoelectric body sensitive to temperature.